These are not real human embryos but probably a cellular construct they contain the cell types similar to those of the human blastocyst. The goal is to understand the mechanisms and molecules that can malfunction and cause genetic diseases or recurrent miscarriages
A group of researchers from the United States and the United Kingdom has announced the creation of a «synthetic human embryonic structure» starting from stamina cells
embryonic, without using ova and sperm. These structures make up the earliest stage of human developmentand scientists say they could one day help increase cunderstanding of genetic diseases or of the causes of natural abortions. Bioengineering teacher Magdalena Zernicka-Goetz described the research work at the International Society for Stem Cell Research’s annual meeting in Boston. The researcher said the work has been accepted by a reputable scientific journal, but has not yet been published. The structures obtained from stem cells, she writes the Guardian, do not have a beating heart or the beginning of a brain, they include only cells that would normally form the placenta, the yolk sac and the embryo itself. Zernicka-Goetz described the cultivation of embryos to one stage just above the equivalent of 14 days of development for a natural embryo (legal limit). “Ours is a three-line human embryo model that specifies amniotic and germ cells, egg and sperm precursor cells,” the professor told the British media. And it’s created from embryonic stem cells.”
Scientists: they are not human embryos
“I want to emphasize that these are not human embryos,” said researcher Zernicka-Goetz herself. “I am embryo models, but are very similar to human embryos and an important pathway to the discovery of many unsuccessful pregnancies. “Be careful because human embryos have not been created as we understand them – he underlines again Manuela Montiprofessor of Embryology and Histology at the University of Pavia — but they were obtained in vitro models by stem cells likely induced to differentiate to form the cell types that form a blastocyst
(a 5-7 day embryo which has a complex structure consisting of about 200 cells, ed), which is the last stage of pre-implantation development».
So what did the working group led by Zernicka-Goetz do? “The work has not yet been published – underlines Professor Monti – however from their statements we understand that human embryonic stem cells were taken, then differentiated, so as to constitute a “cellular construct” which contains the cell types similar to those of the human blastocyst. An analysis of a series of markers was probably carried out which are those specific for the different cells that make up the blastocyst and which will go to make up all the extra embryonic annexes, for example the placenta, or cells which will then give rise to the true embryo is exactly”. In the blastocyst these cells can be distinguished not only by their topographical arrangement but also by the positivity to certain markers. In assembling these cells, it was therefore studied how they are arranged and how they are positive or negative for these markers.
Previous
Positive structures for the same embryo markers have already been assembled in other laboratories around the world and various working groups are working on this kind of research, including the scientist Austin Smithdirector of the Cambridge Stem Cell Institute who in 2021 obtained in test tube a six-day human embryo model.
Understand the reasons for miscarriages and infertility
The scientists say these model embryos could provide crucial aid in studying both genetic diseases and the biological causes of recurrent miscarriages. It should be noted that there is no short-term perspective that synthetic embryos will be used in the clinic and it is also not clear whether these structures can continue to mature beyond the early stages of development.
«The objective of this kind of work, including this one – concludes Manuela Monti – is to understand what are the factors (genes and proteins) that turn on or off during the very early stages of embryonic development. For ethical reasons we cannot use human embryos to understand what induces the arrest of a future pregnancy, so we have to base ourselves either on the animal model or on the cell model. Understanding what are these factors that promote or stop the development of an embryo is important because it could lead to targeted therapies for the treatment of particular pathologies related to infertility, failed implantation, failed pregnancy and prevent natural abortions which occur in percentages much higher than you think”
Ethical issues
The ethical aspect is above all linked to the source, i.e. to the use of human embryonic stem cells and to what extent we can go ahead with the cultures of embryonic stem cells , an aspect already underlined in the other article published by the same scientist who last year had created a «synthetic» mouse embryo with a heart and brain created from stem cells. In the United Kingdom they are working to draw up guidelines to regulate the use of synthetic human embryos.
June 15, 2023 (change June 15, 2023 | 1:09 pm)
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